Oxygen lance for steelmaking furnaces



Nov. 19, 1968 P N ET AL 3,411,716

OXYGEN LANCE FOR STEELMAKING FURNACES Filed May 11, 1966 a wafer! P113. 1.

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2o 12 .9 Oxyggn Out Wafer 00! i i 20 Y 1 2 IN VEIV TORS. RA Ma/v0 c. s TEPHAN and an VIN M. w/L L 5) y At tarney United States Patent OXYGEN LANCE FOR STEELMAKING FURNACES Raymond C. Stephan, Calumet Township, Lake County,

Ind., and Calvin M. Willey, Penn Hills Township, Allegheny County, Pa., assignors to United States Steel Corporation, a corporation of Delaware Filed May 11, 1966, Ser. No. 549,349 Claims. (Cl. 239132.3)

ABSTRACT OF THE DISCLOSURE An oxygen lance having a flow control pipe extending axially inwardly a short distance from the nozzle end of a water-cooled oxygen supply pipe and arranged concentrically with respect thereto, the inner end of the control pipe being in communication with the oxygen supply pipe for the flow of oxygen therethrough. A control plug on the outer end of the control pipe and the nozzle end of said supply pipe have conical facing surfaces which define an outwardly flaring annular orifice through which a ring-like jet of oxygen is discharged, the oxygen flowing through said control pipe being discharged along an axial path extending centrally with respect to the annular orifice about said control plug.

This invention relates, as indicated, to an oxygen lance for steelmaking furnaces and, more particularly, to a nozzle of improved construction that provides an annular orifice from which oxygen is discharged in the shape of an outwardly flaring ring-like jet. In a manner to be described, the lance nozzle of this invention improves the distribution of the oxygen over the surface of a melt of steel in a furnace and eliminates localized wear on the refractory lining of such furnace.

Lances for oxygen steelmaking converters and other furnaces are commonly mounted for axial movement over a vertical path to and from an operative blowing position and usually have a nozzle with a single axially extending orifice therein. In operation, lances of this character inject a single jet of oxygen into the furnace in a vertically downward directional normal to the surface of the molten metal therein and in a manner which causes high localized temperatures and boiling of the molten metal. Although lances with a plurality of angularly inclined nozzle orifices have been proposed for the purpose of distributing the oxygen more uniformly over the surface of the path and to thus reduce localized high temperatures and boiling, such proposals have been found to cause localized wear of the furnace refractories in areas opposite and in line with the lance openings.

One of the principal objects of this invention, accordingly, is to obtain a more uniform and improved distribution of oxygen over the surface of a bath of metal in an oxygen converter in a manner which does not result in localized erosion of the furnace lining. This is accomplished by constructing the lance with an outwardly diverging annular orifice through which the oxygen flows from a centrally located water-cooled oxygen supply pipe so that oxygen is projected therefrom in an outwardly flaring ring-like jet which upon impingement with the molten metal spreads radially outwardly over its surface. A further and related object is to provide a lance of the character indicated with a flow control nozzle orifice arranged centrally of the annular orifice therein for projecting a jet of oxygen along an axial path to increase the spreading movement of said ring-like jet.

Other objects and advantages will become apparent from the following description and the accompanying drawings which show a preferred embodiment of the invention. In the drawings:

3,411,716 Patented Nov. 19, 1968 FIGURE 1 is a longitudinal sectional view, with a central portion thereof broken away, of a lance constructed in accordance with the principles of this invention;

FIGURE 2 is an end view drawn to an enlarged scale anal taken in a direction from the right of FIGURE 1; an

FIGURES 3, 4 and 5 are 'views taken along the lines IIIIII, IV-IV, VV, respectively, of FIGURES 2, 3 and 4.

The lance shown in the drawings comprises a centrally located and water-cooled supply pipe 1 that has a joint 2 at one end for connection in an oxygen supply line (not shown) and a nozzle 3 at its other end. Concentric steel pipes 4 and 5 provide for the circulation of cooling water through the lance in a conventional manner. The pipe 4 defines a chamber 6 about the pipe 1 through which water from an inlet connection 7 circulates in a direction toward the nozzle 3, and the pipe 5 defines a chamber 8 about the pipe 4 through which water circulates in an opposite direction to an outlet connection 9'. A return connection 10 between the chambers 6 and 8 is formed in the nose 11 which forms part of the nozzle 3 and is fabricated from copper. The nose 11 and a connecting sleeve 12 are extensions of the pipe 1 at the nozzle end 3 of the lance and thus constitute part of the supply pipe 1.

The nozzle 3 comprises the nose 11 and a flow control plug 15 of conical shape which is mounted in a central and concentric position therein. The plug 15 and nose 11 respectively, have radially facing conical surfaces 16 and 17 which are concentric and define an annular passage or orifice 18 through which oxygen from the supply pipe 1 is discharged from the nozzle 3 in the form of a ring-like jet. Since the concentric surfaces 16 and 17 diverge outwardly with respect to the axis of the nozzle 3, oxygen is discharged from the orifice 18 in an outwardly flaring ring-like jet with an expanding action which causes it to spread radially outwardly over a wide area of the surface of molten metal in a furnace upon engagement therewith.

The plug 15 is supported in the nozzle 3 by a flow control pipe 20 which has a smaller diameter and extends axially and centrally with respect to the supply pipe 1. At its inner end, the pipe 20 is supported in a concentric position in the supply pipe 1 by a plurality of spacer lugs 21 which are arranged in circumferentially spaced positions about the control pipe 20 and have welded connections with both pipes 1 and 20. The plug 15 is supported by a threaded connection on the outer end of the flow control pipe 20 and has an axially extending opening 22 through which oxygen supplied thereto by the pipe 20 is discharged. The oxygen moving through the opening 22 and the annular passage 18 serves to cool the plug 15 and to prevent skull build-up on the outer end of the lance. An insert 23 in the form of a ring that acts as a lock-nut is threaded on the outer end of the pipe 20 and has a snug fit in a recess 24 in the plug 15. The inner surface 25 of the insert 23 defines the outer end of the oxygen discharge opening 22 and is shaped to provide a centrally located venturi orifice through which a jet of oxygen is discharged along an axial path located centrally of the orifice 18. The jet of oxygen emerging from the central opening or orifice 22 will upon striking the surface of molten metal in a furnace tend to increase the spreading movement of the ring-like jet of oxygen discharged from the orifice 18 and thus improve the distribution of oxygen over the surface of the molten metal.

The major portion of the oxygen is introduced to the furnace bath through the annular nozzle orifice 18. Ideally, the ring-like jet injected from the orifice 18 should strike the furnace bath at a radius about /4 the distance from the furnace axis.

From the foregoing it will be apparent that the lance of this invention effects a wider distribution of oxygen over the surface of a melt of metal in a furnace and thus contributes to improved efficiency of the furnace operation. Attention is particularly directed to the fact that the ring-like jet which is produced by the annular passage or orifice 18 operates to distribute or spread the oxygen radially in all directions over the surface of the metal and that uniform distribution of the oxygen in this manner is effected without any flow concentrations which would cause localized wear or erosion of the furnace refractories. It will also be apparent that the oxygen distributing action of the annular orifice 18 is enhanced by the axial jet of oxygen projected centrally thereof from the nozzle orifice 22 While one embodiment of my invention has been shown and described, it will be apparent that adaptations and modifications may be made without departing from the scope of the appended claims.

We claim:

1. In an oxygen lance, the combination comprising a water-cooled oxygen supply pipe, a flow control pipe arranged concentrically of said supply pipe and extending inwardly a short distance from the discharge end thereof, a flow control plug on the outer end of said control pipe and having an axially extending opening connected therewith, said plug and supply pipe having concentric radially facing and conical surfaces that diverge outwardly in an axial direction and define an outwardly flaring annular orifice through which a ring-like jet of oxygen is discharged from said nozzle, the inner end of said control pipe being in communication with said supply pipe for the flow of oxygen therethrough and its discharge from said control plug opening along an axial path centrally of said ring-like jet, and means at the inner end of said flow control pipe mounting it and said plug concentrically in said supply pipe.

2. An oxygen lance as defined in claim 1 characterized by said mounting means comprising spacer lugs at circumferentially spaced intervals about the outer surface of said control pipe.

3. An oxygen lance as defined in claim 1 characterized by means arranged centrally of said control plug providing a venturi orifice through which oxygen flowing through said control pipe is discharged.

4. An oxygen lance as defined in claim 1 characterized by said control plug having a threaded connection on the outer end of said control pipe.

5. An oxygen lance as defined in claim 4 characterized by said plug having an opening extending axially outwardly from the outer end of said plug, and an insert received in said opening with a venturi orifice therein through which the oxygen is discharged from said control pipe.

References Cited UNITED STATES PATENTS 673,756 5/1901 Burke 239-552 X 1,125,559 1/1915 Kofod 239552 X 1,602,845 10/1926 Burhorn 239552 X 3,130,252 4/1964 Metz 26634 3,216,714 11/1965 Eibl et al 266-34 3,241,825 3/1966 Jilek et al. 26634 FOREIGN PATENTS 174,388 3/1953 Austria.

995,688 6/1965 Great Britain. 1,003,514 9/1965 Great Britain.

M. HENSON WOOD, IR., Primary Examiner.

V. C. WILKS, Assistant Examiner. 

